Summary Transwest Air Flight 203 (TW203), a Beech1900D was en route from StonyRapids to LaRonge, Saskatchewan. WestWind Flight780 (WEW780), a Hawker SiddeleyHS748, was en route from PointsNorthLanding to LaRonge. Both aircraft were operating under instrument flight rules (IFR) and would arrive in LaRonge within minutes of each other. At the time of the occurrence, NavCanada did not provide low level radar service at LaRonge and procedural control was required to facilitate the approach and arrival of TW203andWEW780. At approximately 2031 Universal Coordinated Time (UTC), the crew of WEW780 advised Winnipeg air traffic control that they had departed PointsNorthLanding at a time of 0003UTC. This time was not correct and it was not checked for accuracy by the controller who received it. The flight progress strip for WEW780 was not properly sequenced for arrival at LaRonge and a separation plan was not established for the two aircraft. There was no loss of separation. However, safety was not assured and an air traffic control operating irregularity occurred. Ce rapport est galement disponible en franais. Other Factual Information The Nav Canada Winnipeg Area Control Centre (ACC), North Specialty, is responsible for air traffic control of flights that operate in northern Saskatchewan, Manitoba, and Ontario. The specialty consists of several subsections or positions known as sectors. Depending on traffic levels, all sectors may be staffed. During low traffic levels, some sectors are combined. This report will focus on events which took place at the combined LaRonge/north low (northlow) sector position of the Winnipeg North Specialty. North low may be staffed by either one or two controllers. At times of lower traffic volumes, one controller assumes responsibility for both the radar and data positions. The radar position communicates with aircraft via radio, and where radar is available, monitors aircraft progress on a radar indication module. The data position is responsible for sequencing flight progress strips, computing and entering data onto the strips and into the computer, and communicating with other sectors within and outside the ACC. When one person fills both positions, he or she carries out all duties for the data and radar positions. Until just before the occurrence, the duties of both radar and data positions in the north low sector were being performed by one controller. A position handover briefing was being conducted when WestWind Flight780 (WEW780) first contacted the north low controller, and shortly thereafter a second controller joined the north low sector. A review of the company's documentation revealed that all personnel were adequately rested prior to this occurrence and were qualified to perform the duties assigned to them. When flight crews file instrument flight rules (IFR) flight plans, information from the flight plan is entered into the national flight data processing system (NFDPS) computer. The computer uses this information and generates flight progress strips for use by controllers. Two strips for each aircraft were printed, one to provide the controller with departure and en route airspace information, the other for arrival information at the destination. The printed strips are slotted into plastic holders and placed in a pending, non-active bay on the flight data board until activated upon receipt of an estimate by the north low specialty controller. The active strip is then sequenced with others on the flight data board in order of arrival times. The flight data board is divided into a number of sections headed by a fix designator. The objective is to post each strip depicting an aircraft's route under the most appropriate fix designator, so that potential conflicts can be more easily recognized and accurately assessed. At 2007 UTC1, the north low controller received, from Edmonton ACC, a StonyRapids departure time of2002 for TranswestAir Flight203 (TW203). The north low controller then entered the departure time and an estimated time en route (ETE) for abeam Key Lake of 29minutes on the departure flight progress strip and placed it under the Wollaston/Key Lake header. The controller also entered an ETE of 24minutes on TW203's arrival strip and sequenced this strip under the La Ronge header of the flight data board. At 2028:35, the crew of TW203 advised Winnipeg ACC that they were passing abeam Key Lake en route to LaRonge (seeAppendixA) at flight level (FL)250. The north low controller entered the abeam Key Lake time on the TW203 en route strip and calculated an estimated time of arrival (ETA) of 2054 for LaRonge. The level of air traffic in the sector was starting to increase from light to moderate at this time, and the complexity was judged to be moderate. At 2031:22 the crew of WEW780 called Winnipeg ACC directly on the air traffic control frequency. The north low controller did not hear the call sign of the aircraft and asked the caller to repeat. The pilot of WEW780 stated that the flight had departed PointsNorth at 0003 and was at 15000feet, 100nautical miles north of LaRonge. In fact, WEW780 had departed PointsNorth at 2003. The first north low controller had started a position handover briefing to the relieving controller and asked WEW780 to standby for a clearance. The first north low controller did not detect the time discrepancy and the second controller had not heard the radio communication between the pilot and the controller because he was waiting for the handover briefing to be completed prior to plugging in his headset. The first north low controller interrupted the handover briefing and wrote the pilot reported departure time of 0003 - without considering that this was about 3hours in the future - and aircraft position on the departure strip, and placed it in the bay of the flight data board under the Wollaston/Key Lake header. Nav Canada's Air Traffic Control Manual of Operations (ATCMANOPS) requires that air traffic controllers determine estimates and confirm pilot reported estimates, but the ATC MANOPS does not specifically require controllers to check the accuracy of pilot reported departure times. Controllers normally check the accuracy of times communicated to them as a standard safety practice. ATC separation is based on controller calculated times. The ATCMANOPS contains procedures that require a controller to place (cock) progress strips in an angled, conspicuous manner in the bay when further action is required. In this occurrence, all actions concerning WEW780 had not been completed at the time the second north low sector controller assumed responsibility for the sector. It could not be determined whether the first north low controller intended any further action with respect to the flight progress strips for WEW780 or if he cocked either of them to indicate that further action was required. A review of the Nav Canada tape recordings and transcripts revealed much radio and inter-specialty communication taking place between 2031 and 2040. Significant background noise could also be heard on the audio tapes. During this time period, the first north low controller attempted to complete his handover briefing but was interrupted several times. Extraneous communication can increase a person's thought and workload process to the point where it becomes difficult for an individual to concentrate on the task at hand. Interruptions in a sequential process may result in some actions not being taken. At the point in the handover briefing where he was to discuss WEW780, the first controller pointed to the flight progress strips and expressed his relief that WEW780 had checked in and was standing by for a clearance. On completion of the handover briefing, the first controller stood back, confirmed that he had completed all required action for the handover briefing in accordance with the transfer of position checklist, then left. Both controllers were satisfied that the handover (transfer of position checklist) had been completed satisfactorily. The transfer of position checklist requires that a relieving controller be advised of any conflicting traffic. However, the information with respect to WEW780 and TW203 had not been analysed and potential conflict was not detected at the time of the handover. Nav Canada's checklist requires a certain level of analysis and relies on knowledge-based methodology to accomplish its intended purpose. That is, the categories in the transfer of position checklist are composed of broad-based concepts rather than a detailed, step-by-step list. Human factors studies have shown that knowledge-based problem solving can facilitate the performance of extremely complex tasks. However, in heavy workload or high stress situations knowledge-based task management is more susceptible to error than is rule- or procedure-directed task management.2 At 2033:08, the second north low controller cleared WEW780 to LaRonge and assigned the flight an altitude of 15000feet. Shortly thereafter, he calculated WEW780's ETA for LaRonge, using the ETE from PointsNorth to LaRonge of 54minutes that the first controller had calculated with the Winnipeg inertial navigation simulator. Adding the ETE to the departure time of 0003, the second controller wrote the arrival time for LaRonge of 0057 onto the WEW780 arrival strip and sequenced this strip at the top of the LaRonge bay. As with the first controller, the second controller did not consider that the departure time was about 3hours in the future. Also, the second controller did not recognize that the aircraft would not land for over 4hours and 20minutes. To assist the second controller, a third controller arrived at the sector at approximately 2035:40 and took over the duties of the radar position. The second controller then assumed responsibility for the data position. Approximately two minutes later, TW203 requested a descent clearance, and the third controller issued a clearance to maintain 9000 feet above sea level (asl). This clearance authorized TW203 to descend through the altitude of WEW780. At this point, the data (second) controller asked the radar (third) controller to request WEW780's estimate for LaRonge. At 2039:15, the pilot of WEW780 replied that they were estimating LaRonge in 15minutes. The data controller then corrected the ETA on WEW780's arrival strip to 2055, but did not re-sequence the strip in the LaRonge bay according to the appropriate order of arrival at LaRonge. At this point, neither controller detected the potential conflict between the aircraft. ATC MANOPS 901.8 requires controllers to ensure that flight progress strips are arranged in the appropriate order when data has been entered onto them. At 2043:35, the north low radar controller issued TW203 an approach clearance for LaRonge. At 2045:13, after TW203 had been issued an approach clearance, WEW780 called ATC and requested a descent clearance. At this point the radar controller realized that these two aircraft were in close proximity to each other. After determining the passing altitude for TW203, he instructed TW203 to stop the descent at 16000feet. The radar controller then asked both aircraft for their distance from LaRonge: TW203 was 34DME3 north of LaRonge, and WEW780 was 40DME north. The minimum spacing required before clearing one aircraft to descend through the altitude of another aircraft was 5DME. Once TW203 acknowledged the descent altitude of 16000feet, the minimum required separation was achieved. Situational awareness is a term used to describe the level of understanding displayed by an individual in a given situation. Two of the components of situational awareness are the individual's perception of the situation, and the reality of the situation. When a person's perception of the situation differs from reality, he or she is said to have experienced a loss of situational awareness. ATC MANOPS 471.A requires controllers to have a plan to ensure separation between aircraft that are operating in such proximity of each other as determined by ATCMANOPS separation standards. Formulation and implementation of such a plan requires awareness of the specified aircrafts' proximity, which the controllers involved in this occurrence lacked.